text: 'use strict';
  
  var hasOwn = Object.prototype.hasOwnProperty;
  var toString = Object.prototype.toString;
  
  var isFunction = function isFunction(fn) {
  	var isFunc = typeof fn === 'function' && !(fn instanceof RegExp) || toString.call(fn) === '[object Function]';
  	if (!isFunc && typeof window !== 'undefined') {
  		isFunc = fn === window.setTimeout || fn === window.alert || fn === window.confirm || fn === window.prompt;
  	}
  	return isFunc;
  };
  
  module.exports = function forEach(obj, fn) {
  	if (!isFunction(fn)) {
  		throw new TypeError('iterator must be a function');
  	}
  	var i,
  	    k,
  	    isString = typeof obj === 'string',
  	    l = obj.length,
  	    context = arguments.length > 2 ? arguments[2] : null;
  	if (l === +l) {
  		for (i = 0; i < l; i++) {
  			if (context === null) {
  				fn(isString ? obj.charAt(i) : obj[i], i, obj);
  			} else {
  				fn.call(context, isString ? obj.charAt(i) : obj[i], i, obj);
  			}
  		}
  	} else {
  		for (k in obj) {
  			if (hasOwn.call(obj, k)) {
  				if (context === null) {
  					fn(obj[k], k, obj);
  				} else {
  					fn.call(context, obj[k], k, obj);
  				}
  			}
  		}
  	}
  };